固化废弃软黏土的强度特性及水稳定性研究

硅酸盐通报 ›› 2022, Vol. 41 ›› Issue (3): 976-984.

固化废弃软黏土的强度特性及水稳定性研究

易昕政¹, 骆睿栋¹, 高游¹, 于海浩², 铁宁¹, 姚梦晗¹

1.宁波大学土木与环境工程学院,宁波 315000;
2.广西岩土力学与工程重点实验室,桂林 541004

收稿日期:2021-10-15 修回日期:2021-12-23 出版日期:2022-03-15 发布日期:2022-04-08
通讯作者: 于海浩,副教授。E-mail:2018094@glut.edu.cn
作者简介:易昕政(2001—),男。主要从事固化土研究。E-mail:1241558315@qq.com
基金资助:
国家级大学生创新创业训练项目(202111646002);宁波市科技计划(2019B10048);广西自然科学基金(2019GXNSFAA245025)广西岩土力学与工程重点实验室资助(20YKF06)

Research on Strength Behavior and Water Stability of Solidified Waste Soft Clay

YI Xinzheng¹, LUO Ruidong¹, GAO You¹, YU Haihao², TIE Ning¹, YAO Menghan¹

1. School of Civil and Environmental Engineering, Ningbo University, Ningbo 315000, China;
2. Guangxi Key Laboratory of Geomechanics and Geotechnical Engineering, Guilin 541004, China

Received:2021-10-15 Revised:2021-12-23 Online:2022-03-15 Published:2022-04-08

摘要/Abstract

摘要： 为了提高水泥和粉煤灰固化高含水率废弃软黏土的固化效果,选取水玻璃作为外加剂,吸水性强的生石灰作为分散剂,采用无侧限抗压强度试验、X 射线衍射、扫描电镜试验研究掺量与龄期对固化软黏土水稳定性和强度特性的影响。试验结果表明,3%(质量分数)的水泥、7%(质量分数)的粉煤灰、2%(质量分数)的生石灰与2%(质量分数)的水玻璃复合时能较好提高高含水率软黏土固化后的强度和水稳定性,其强度能达到水泥粉煤灰类基底层最低强度(1 MPa)。在水泥、粉煤灰和水玻璃质量掺量相同情况下,生石灰质量掺入比由0%增加至2%,其强度增大约375 kPa,且有利于后续固化剂的均匀搅拌,说明生石灰的减水和分散效应在固化土中起主导作用。此外,扫描电镜结果显示加入复合固化剂后大集聚体消失,产生大量的片状结构,大孔隙被填充,土体的强度也随之提高。

关键词: 软黏土, 固化, 无侧限抗压强度, 配合比, 水稳定性, 固化机理

Abstract: In order to improve the effects of cement and fly ash on the solidification of waste soft clay with high water content, sodium silicate and quick lime were selected as additive and dispersing agent, respectively. The unconfined compressive strength test (UCS), X-ray diffraction (XRD), and scanning electron microscope (SEM) were used to research the influences of mixing ratio and age on the water stability, strength behavior, solidification mechanism of solidified waste soft clay. The results show that 3% (mass fraction) cement combined with 7% (mass fraction) fly ash, 2% (mass fraction) quick lime and 2% (mass fraction) sodium silicate significantly improve the strength and water stability of solidified soft clay. The strength of solidified soft clay reaches 1 MPa, and meets the strength requirements of the cement-fly ash base layer. With the same mixing ratio of cement, fly ash and water glass, the mass fraction of quick lime increases from 0% to 2%, and its strength increases about 375 kPa. Adding the quick lime is conducive to the uniform mixing of the other curing agents. It indicates that the water absorption and dispersion effect of quick lime play a vital role in the solidified soil. In addition, SEM images show that after adding the composite curing agent, the large aggregates disappear, a large number of sheet structures generate, the large pores between the particles are filled, and the strength of soft soil is also improved.

Key words: soft clay, solidification, unconfined compressive strength, mixing ratio, water stability, curing mechanism

中图分类号:

TU447

易昕政, 骆睿栋, 高游, 于海浩, 铁宁, 姚梦晗. 固化废弃软黏土的强度特性及水稳定性研究[J]. 硅酸盐通报, 2022, 41(3): 976-984.

YI Xinzheng, LUO Ruidong, GAO You, YU Haihao, TIE Ning, YAO Menghan. Research on Strength Behavior and Water Stability of Solidified Waste Soft Clay[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2022, 41(3): 976-984.

参考文献

[1] 孙德安,陈波,周科.重塑上海软土的压缩和剪切变形特性试验研究[J].岩土力学,2010,31(5):1389-1394.
SUN D A, CHEN B, ZHOU K. Experimental study of compression and shear deformation characteristics of remolded Shanghai soft clay[J]. Rock and Soil Mechanics, 2010, 31(5): 1389-1394 (in Chinese).
[2] 李方明,高波,朱利明,等.软土层地连墙施工对邻近浅基础房屋影响研究[J].自然灾害学报,2018,27(1):81-87.
LI F M, GAO B, ZHU L M, et al. Study on the influence of diaphragm wall construction of soft soil ground on adjacent shallow foundation building[J]. Journal of Natural Disasters, 2018, 27(1): 81-87 (in Chinese).
[3] 乔京生,王旭影,王冠泓,等.粒化高炉矿渣微粉固化淤泥质土的动力特性及微观机理[J].硅酸盐通报,2021,40(7):2306-2312.
QIAO J S, WANG X Y, WANG G H, et al. Dynamic characteristics and microscopic mechanism of muddy clay solidified by ground granulated blast-furnace slag[J]. Bulletin of the Chinese Ceramic Society, 2021, 40(7): 2306-2312 (in Chinese).
[4] 朱思迪,顾强康,姚志华.外加剂对水泥-水玻璃固化软土影响效果试验研究[J].硅酸盐通报,2016,35(10):3112-3118.
ZHU S D, GU Q K, YAO Z H. Effect of admixtures on cement-sodium silicates stabilized soft soils[J]. Bulletin of the Chinese Ceramic Society, 2016, 35(10): 3112-3118 (in Chinese).
[5] 孙秀丽,童琦,刘文化,等.碱激发粉煤灰和矿粉改性疏浚淤泥力学特性及显微结构研究[J].大连理工大学学报,2017,57(6):622-628.
SUN X L, TONG Q, LIU W H, et al. Study of microstructure and mechanical properties of dredged silt solidified using fly ash and slag stimulated by alkali[J]. Journal of Dalian University of Technology, 2017, 57(6): 622-628 (in Chinese).
[6] 王伟齐,孙红,葛修润.碱激发作用下海相软土固化研究[J].硅酸盐通报,2021,40(7):2248-2255+2269.
WANG W Q, SUN H, GE X R. Solidification of marine soft soil under alkali excitation[J]. Bulletin of the Chinese Ceramic Society, 2021, 40(7): 2248-2255+2269 (in Chinese).
[7] 俞家人,陈永辉,陈庚,等.地聚物固化软黏土的力学特征及机理分析[J].建筑材料学报,2020,23(2):364-371.
YU J R, CHEN Y H, CHEN G, et al. Mechanical behaviour of geopolymer stabilized clay and its mechanism[J]. Journal of Building Materials, 2020, 23(2): 364-371 (in Chinese).
[8] 韩天,于佳丽,吴燕开.硫酸钠激发钢渣粉活性改良水泥土试验研究[J].科学技术与工程,2019,19(7):231-238.
HAN T, YU J L, WU Y K. Experimental study on sodium sulfate exciting steel slag power activity and improving cement soil[J]. Science Technology and Engineering, 2019, 19(7): 231-238 (in Chinese).
[9] GARCÍA GIMÉNEZ R, VIGIL DE LA VILLA R, GOÑI S, et al. Fly ash/paper sludge as constituents of cements: hydration phases[J]. Journal of Environmental Engineering and Science, 2015, 10(3): 46-52.
[10] HILT G H, DAVIDSON D T. Lime fixation in clayey soils: RB Bulletin No.262[J]. Highway Research Board, National Research Council, 1960: 20-32.
[11] 中华人民共和国交通运输部.公路沥青路面设计规范:JTG D50—2017[S].北京:人民交通出版社,2017.
Ministry of Transport, PRC. Design code for highway asphalt pavement: JTG D50—2017[S]. Beijing: People's Communications Press, 2017 (in Chinese).
[12] 王东星,何福金.CO₂碳化-矿渣/粉煤灰协同固化土效果与机制研究[J].岩石力学与工程学报,2020,39(7):1493-1502.
WANG D X, HE F J. Investigation on performance and mechanism of CO₂ carbonated slag/fly ash solidified soils[J]. Chinese Journal of Rock Mechanics and Engineering, 2020, 39(7): 1493-1502 (in Chinese).
[13] 徐日庆,邓祎文,徐波,等.基于SEM图像的软土三维孔隙率计算及影响因素分析[J].岩石力学与工程学报,2015,34(7):1497-1502.
XU R Q, DENG Y W, XU B, et al. Calculation of three-dimensional porosity of soft soil based on SEM image[J]. Chinese Journal of Rock Mechanics and Engineering, 2015, 34(7): 1497-1502 (in Chinese).
[14] 聂轶苗,刘淑贤,张晋霞,等.粉煤灰的活性研究及进展[J].粉煤灰综合利用,2013,26(3):52-56.
NIE Y M, LIU S X, ZHANG J X, et al. The research progress and developing prospect of fly ash activity[J]. Fly Ash Comprehensive Utilization, 2013, 26(3): 52-56 (in Chinese).
[15] 简文彬,张登,黄春香.水泥-水玻璃固化软土的微观机理研究[J].岩土工程学报,2013,35(s2):632-637.
JIAN W B, ZHANG D, HUANG C X. Micromechanism of cement-sodium silicate-stabilized soft soils[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(s2): 632-637 (in Chinese).
[16] 柯国军,杨晓峰,彭红,等.化学激发粉煤灰活性机理研究进展[J].煤炭学报,2005,30(3):366-370.
KE G J, YANG X F, PENG H, et al. Progress of research on chemical activating mechanisms of fly ash[J]. Journal of China Coal Society, 2005, 30(3): 366-370 (in Chinese).
[17] 王敏,吴勇生,李如燕,等.碱激发剂对铸造粉尘-粉煤灰基地质聚合物抗压强度的影响[J].硅酸盐通报,2013,32(6):1037-1042.
WANG M, WU Y S, LI R Y, et al. Effects of alkali-activator on compressive strength of casting dust-fly ash based geopolymer[J]. Bulletin of the Chinese Ceramic Society, 2013, 32(6): 1037-1042 (in Chinese).